Satellites

I had basic information related Amateur Radio Satellites also called as OSCAR’s (Orbiting satellites carrying amateur radio) from my early days as a Radio HAM but never tried to use them as my licence category does not have privileges for Amateur satellite communications. My interest was driven when I started to follow Mike,DK3WN and his telemetry decoding activities, Cubesats launches were gaining momentum using amateur radio frequencies,this was a wonderful opportunity for me to learn about satellite communication. I was also tracking the progress of the International Space station (ISS) and the Amateur Radio capability being setup by ARISS. Some videos of my activities are available for viewing on my channel on YouTube.

I was reading plenty of material that was available on the Internet related to this topic and installed Orbitron to track the satellites.

I started to listen on the satellite down-link frequencies on 2 Meters FM using a ICOM 02AT handheld transceiver with a J pole and Slim Jim antenna, I could hear QSO’s thru UO-14 , AO51 and some other satellites. I realized that I need to improve my station for my primary interest to decode telemetry from the cubesats. I managed to procure a ICOM 821H all mode VHF/UHF transceiver and this helped me to hear signals on sideband and CW as well. The next critical piece that was missing was a decent antenna for which I built a six element yagi for 2 meters and eight element 70 cms elements mounted on the same boom.The antennas were connected by two separate RG213 coaxial cable to the radio. I also managed to procure a used channel master TV antenna rotator which served for Azimuth rotation only. This antenna is still in use from 2005 and is performing well.

To decode telemetry from the satellites using the applications provided by the satellite project teams I had to interface my Radio to the computer to communicate with sound card based software and TNC. For the sound card interface I am using the Signalink USB + AGWPE and other applications developed by the satellite project teams and Mike, DK3WN. I also have MFJ 1278 TNC and Kantronics 9612 (for 9600 baud data) all wired to the Radio using multiple RS232 ports and dual sound card on the PC, this setup eliminates the need to switch cables between the TNC’s and Audio feed to the sound card. I have recently been using software based TNC for 1200 / 9600 baud developed by UZ7HO with great success.

Automatic doppler correction from the Orbitron Satellite tracking application + WispDDe is achieved by using a Digimaster USB CAT Interface from ZLP electronics which is connected to the ICOM 821H.

My mentor for the Telemetry Decoding is Mike, DK3WN who helped me to get started and took time to answer all my questions and continues to help with my queries. I am at active contributor to his Satblog,visit www.dk3wn.info for more information on his accomplishments and resources that he has made available for the Amateur Radio fraternity.

I have a good collection of QSL cards sent by satellite project teams for submitting the telemetry reception reports and is available in the satblog section of my website. Many such projects leverage on the Amateur Radio fraternity to submit reception reports of beacon and decoding of telemetry data which can be sent real time.

There has been significant development’s in SDR (Software Defined Radios) technology and I wanted to try this capability and purchased a Funcube Dongle Pro. This has enhanced the capability of my station by eliminating the dependency on the Radio for receiving signals from the satellites. Thanks to AMSAT UK , Radio Communication Foundation (RCF) and not to forget Howard, G6LVB for coming up with this innovative device which has opened up a new dimension for those who are interested to listen to the signals from Amateur Satellites. I use SDRSharp application with Orbitron + satellite tracker plugin to listen to the Amateur Radio satellites.

Another nice software I use is AGW Online Kiss developed by my good friend Mike, DK3WN, this software works together with AGW packet engine and gives the opportunity to decode AX25 telemetry in kiss mode without a hardware modem.

I have provided ground station support (Receive only) for Telemetry decoding for many satellite projects which have their down link on the Amateur Radio frequencies and have a nice collection of QSL cards sent by those project teams. Below are some of them.

How can I forget to mention some things I have done related to Amateur Radio on the International Station.

ISS Achievement Award for working the ISS on Packet, Repeater and Voice.

QSO with Astronauts Bill McArthur & Richard Garriott from the ISS.

Participated in the Shadow experiment

Active Satellite Gateway for APRS traffic from ISS.

Received two beautiful QSL card’s and PIN for decoding telemetry from Delfi n3Xt and Delfi C3.